At June 2012, the estimated resident population of Western Australia (WA) was 2.43 million people, which represented 11% of the total Australian population. WA's population increased by 3.3% (or 78,000 people) between 2011 and 2012. This was the fastest growth of all the states and territories, and much higher than the national figure of 1.6%.

At June 2012, the population of Greater Perth was 1.90 million people, which was 78% of the state's total population. Between 2011 and 2012, Greater Perth increased by 65,400 people, or 3.6%. This was the fastest growth of all capital cities in Australia.

The largest population growth in WA in 2011-12 occurred in the outer suburban fringes of Greater Perth. The south-west SA2 of Baldivis had the largest increase, up by 2,800 people. Ellenbrook in the north-east and Forrestdale - Harrisdale - Piara Waters in the south-east followed, increasing by 2,400 and 1,800 people respectively. Large growth was also recorded in the north-western SA2s including Butler - Merriwa - Ridgewood (up 1,600 people), and Madeley - Darch - Landsdale and Yanchep (both 1,500).

Forrestdale - Harrisdale - Piara Waters in the south-east was the fastest-growing SA2 within Greater Perth in 2011-12, increasing by 24% to reach 9,600. This was followed by Yanchep, Baldivis, Byford and Bertram - Wellard (West), all located in the outer suburban fringes of Greater Perth, which each increased by over 12%.

Between June 2011 and June 2012, the remainder of WA grew by 12,600 people (or 2.4%) to 532,700. This represented 22% of the state's population.

Bunbury recorded the largest population increase (up 2,600 people) of all SA3s outside of Greater Perth in the 12 months to 2012. Pilbara in the north-west followed with an increase of 2,200 people. The fastest population increase was in Augusta - Margaret River - Busselton (up 3.9%), followed by the Pilbara (3.5%).

Of all SA2s outside of Greater Perth, Busselton in the south-west of the state and Karratha in the north-west had the largest population growth, each with an increase of 880 people. These were followed by Australind - Leschenault (up 830 people) in the south-west and Broome (440) in the north-west.

Australind - Leschenault had the fastest growth, at 5.5%. This was followed by Karratha and Port Hedland in the Pilbara, which both grew by 5.1%.

Population decline

No SA3s in the remainder of WA declined in population in 2011-12.

Population declined in just five of the 77 SA2s in the remainder of WA. These included the wheatbelt areas of Merredin (down 1.5% or 80 people) and Kulin (down 0.9% or 40 people).

WA's population density at June 2012 was 1.0 person per square kilometre (sq km). This was the second lowest of all the states and territories after the Northern Territory (0.2 people per sq km), and compares with 3.0 people per sq km for Australia as a whole.

Greater Perth had a population density of 300 people per sq km at June 2012, while the remainder of WA had just 0.2 people per sq km. In the year to June 2012, the density of Greater Perth increased by 10 people per sq km.

The highest population densities in Greater Perth were in the north-western SA2s of Tuart Hill - Joondanna (3,400 people per sq km), Scarborough (3,200), and Innaloo - Doubleview (3,000). North Perth, Mount Hawthorn - Leederville and Nollamara - Westminster also had densities of more than 2,800 per sq km. All of these SA2s have an area of 6.0 sq km or less.